1. Field of the Invention
The present invention relates to a pressure gauge, and more particularly to a mechanical pressure gauge having a digital output displayed by a digital diaplayer.
2. Description of the Prior Art
As shown in FIG. 1, a typical mechanical pressure gauge is illustrated and comprises a Bourdon tube 11 coupled to a pressurized fluid reservoir with a port 19 of a housing or a support 10, a pinion 14 and a pointer 16 rotatably supported on support 10 with a spindle 17, and a sector gear 13 rotatably secured on the support 10 and coupled to the Bourdon tube 11 with a link 12 and engaged with the pinion 14. The sector gear 13 may rotate the pinion 14 and thus the pointer 16 to indicate the pressure value when the sector gear 13 is rotated by the Bourdon tube 11 via the link 12 and when the Bourdon tube 11 is deformed by the pressurized fluid that flows into the Bourdon tube 11. A spring 15 is engaged on the spindle 17 and engaged with the support 10 for recovering the spindle 17 after the pressure is released from the support 10. However, the pointer 16 may be used to display or to point an analog output only and may not be used to exactly tell the value of the pressure.
As shown in FIG. 2, illustrated is a typical electric pressure gauge including a pressure sensor 21 engaged in a tube 20 and coupled to an electric circuit 23 for sensing or detecting the pressure in the tube 20. One or more batteries 22 are received in a housing 27 and coupled to the electric circuit 23 for energizing the electric circuit 23 and/or the pressure sensor 21. The electric circuit 23 may convert the pressure in the tube 20 into a digital output which may be displayed in the displayer 24. However, the pressure sensor 21 is rather expensive, and the pressure sensor 21 includes a highly precision configuration that may not be easily manufactured.
The present invention has arisen to mitigate and/or obviate the afore-described disadvantages of the conventional pressure gauges.
The primary objective of the present invention is to provide a pressure gauge including a mechanical configuration and including a digital output for precisely showing and displaying the value of the pressure.
In accordance with one aspect of the invention, there is provided a pressure gauge comprising a housing, a Bourdon tube coupled to a pressure reservoir for receiving a pressurized fluid, a spindle supported on the housing, a link device for coupling the Bourdon tube to the spindle and to rotate the spindle in correspondence with a pressure in the Bourdon tube, a displayer, and a device for converting a rotational movement of the spindle to a digital output and to be displayed in the displayer. The rotational movement of the spindle and the deformation or the movement of the Bourdon tube may thus be converted into the digital output and may be precisely shown in the displayer.
The link device includes a pinion secured on the spindle and rotated in concert with the spindle, a sector gear rotatably secured in the housing and engaged with the pinion, and a link coupled between the Bourdon tube and the sector gear for rotating the pinion via the sector gear.
A spring-biasing device is further provided for recovering the spindle when the pressure in the Bourdon tube is released.
The rotational movement converting device includes a disc secured to the spindle and rotated in concert with the spindle, the disc includes a peripheral portion having a plurality of openings formed therein, and a photo detecting device for detecting a rotational movement of the disc.
The photo detecting device includes a gap formed therein for receiving the peripheral portion of the disc, a light emitting device disposed on a first side of the disc, and a detector disposed on a second side of the disc for detecting a light generated by the light emitting device and transmitted through the openings of the disc.
The rotational movement converting device further includes an electric circuit coupled between the displayer and the photo detecting device for receiving a detected signal from the photo detecting device.
One or more batteries may further be provided for energizing the electric circuit.
Further objectives and advantages of the present invention will become apparent from a careful reading of a detailed description provided hereinbelow, with appropriate reference to accompanying drawings.